The present invention is related generally to touch-sensitive display screens, and, more particularly, to providing feedback to a user of a touch-sensitive display screen.
Many computing applications require some amount of data entry. Some applications call for only a very limited number of characters, such as when a user enters a password or a PIN. Other applications, for example word processing or e-mail, require the user to enter extended amounts of data. For these latter applications, the keyboard reigns as the supreme data-entry device. Its design has been fashioned over more than a century to take advantage of people""s nature manual dexterity. Today, typing on a keyboard is a common skill, and its supporting hardware and software are standardized and cheap.
Recently, small portable computing devices that support some form of data entry have become common. Such devices, typically smaller than a laptop computer, include, for example, cellular telephones, two-way pagers, and personal digital assistants. Often, these devices include a touch-sensitive display screen that serves both to display output from the computing device to its user and to receive input from the user. For some applications, the user xe2x80x9cwritesxe2x80x9d with a stylus on the screen. The user""s handwriting is decoded and becomes input to the computing device. In other applications, the user""s input options are displayed as control icons on the screen. When the user selects an option by touching the icon associated with the option, the computing device detects the location of the touch and sends a message to the application or utility that presented the icon.
These devices often do not include a keyboard. To enter text, a xe2x80x9cvirtual keyboard,xe2x80x9d typically a set of icons that look like the keycaps of a traditional keyboard, are painted on the screen. The user xe2x80x9ctypesxe2x80x9d by successively touching areas on the screen associated with specific keycap icons. This method works well for applications that require minimal data entry and where speed of entry is not a concern.
However, advancing data processing and communications technologies are enabling these small portable devices to support more sophisticated applications, specifically applications that call for extended data entry. As one interesting example, consider a recently introduced tablet-like detachable monitor supported by a host computing device, the host typically a personal computer (PC) sitting in a fixed location. The tablet has a touch-sensitive display screen. The tablet, once detached from the host, communicates wirelessly with the host and operates as a portable input/output device. A user carries the tablet around an office or home, using the tablet to gain access to applications running on the fixed-location host. Some of these applications, for example e-mail, word processing, and Web browsing, require extended text entry.
As experience with this tablet and with other increasingly capable portable devices has hinted, extensive data entry would be facilitated by a more robust data-entry mechanism than a stylus (or finger) on a virtual keyboard. Extensive typing on a virtual keyboard is a slow and tedious process, partly because a user must continually correct the position of his fingers over the keycap icons. A traditional hardware keyboard provides finger-positioning feedback via the indented surfaces of the keys. Touch-sensitive display screens are flat to allow good viewing, but their flatness does not provide such tactile feedback. As another hindrance to quick typing, these screens are also quite rigid with essentially no xe2x80x9cgivexe2x80x9d to tell the user that a virtual key has been pressed.
Several attempts have been made to add a hardware keyboard to a small portable device, but none of these attempts has led to a satisfactory mechanism for extended data entry. One problem lies in the size of the hardware keyboard: full-size keyboards are cumbersome to carry around, detracting from the very portability that defines these devices, while smaller keyboards, useful for limited data-entry applications, do not comfortably accommodate the human hand to allow for rapid and extended typing.
What is needed is a way to make a touch-sensitive display screen into a more acceptable extended data-entry device. The utility of such a device would not be limited to portable display devices, but would enhance the experience of entering data on any touch-sensitive display screen.
In view of the foregoing, the present invention provides a xe2x80x9ckeyboard overlayxe2x80x9d that sits on top of a touch-sensitive display screen of a computing device. After aligning the keyboard overlay on the display screen, the user types on the keyboard overlay. When the user presses a key on the keyboard overlay, the pressure is transmitted to the touch-sensitive display screen below. That pressure is registered by the display screen as a touch. The keyboard overlay is formed to provide tactile finger-position feedback so that a user can keep his fingers oriented properly over the keyboard. Some embodiments additionally supply feedback when the user presses a key hard enough to register on the display screen. The keyboard overlay, in combination with the touch-sensitive display screen, allows the user to type almost as conveniently and as quickly as on a traditional hardware keyboard.
In some embodiments, the keyboard overlay is formed from an opaque, rubbery plastic. Keycap information is displayed in the key areas of the overlay. In other embodiments, the overlay is transparent, allowing a user to see a virtual keyboard painted on the touch-sensitive display screen below. Some applications may blend the virtual keyboard display with other display information below the keyboard overlay.
When not in use, the keyboard overlay is removed from the touch-sensitive display screen. Flexible embodiments of the keyboard overlay may be rolled up, and rigid embodiments may be stored on a pocket of the computing device.
The touch-sensitive display screen can continue to operate as it always has, and the computing device need not even be aware of the presence of the keyboard overlay. If, however, the computing device becomes aware of the presence of the keyboard overlay, then it can modify its behavior accordingly. For example, an application running on the computing device can switch to a text-entry mode when a keyboard overlay is detected. As part of the switch, the application can paint a virtual keyboard under the keyboard overlay that matches the size and key positions of the overlay. The application moves other display information to parts of the screen not covered by the overlay.
In some embodiments, the computing device knows not only that a keyboard overlay is present, but also knows the type of the overlay. In one embodiment, the keyboard overlay contains active or passive electronic components (for example, wire jumpers, resistors, or even an electronic chip) that are powered by the computing device when the overlay is put in place. The computing device queries the electronic components to know the type of the overlay. Applications may respond differently to different types of overlays. Further, different applications may be invoked depending upon the type of overlay detected. For example, an overlay that looks the keypad of a calculator may bring up a calculator application designed to work with that keypad.
Some embodiments of the keyboard overlay incorporate a rigid frame in addition to soft plastic key areas. The frame serves to align the keyboard overlay with respect to the touch-sensitive display screen and physically isolates each key area from its neighbors, preventing pressure on one key area from blurring over into adjacent key areas.